Whenever I unsubscribe from a mailing list, I see that they say something like 'The change will take effect in 10 days/30 days/etc'. I would assume unsubscribing is just removing my email from some database. What is the idea behind making me wait so many days?
Edit: Since this question is close here as off-topic, I have opened it here in Superuser.
Closed in Superuser too. So rephrasing the question here.